Technical Field
The present invention relates to a piezoelectric device, an ultrasonic device including the piezoelectric device, and a probe, an electronic apparatus, an ultrasonic imaging apparatus, and the like using the ultrasonic device.
Related Art
In ultrasonic transducers, an opening is formed in a base made of silicon. The opening is closed by a vibration film. A piezoelectric element is supported on a surface of the vibration film. A barrier layer is laminated on the surface of the vibration film. The barrier layer is sandwiched between the piezoelectric element and the vibration film. The barrier layer prevents a chemical interaction between the piezoelectric element and the vibration film. The vibration film may be formed of silicon oxide, silicon carbide, silicon nitride, or other silicon-based materials. The barrier layer may be formed of Al2O3, ZrO2, TiO2, HfO2, MgO, or LaAlO2. JP-A-2002-271897 is an example of related art.
As in the case where, for example, an acoustic matching material is filled in the opening, water and moisture may enter the opening. In this case, in a space within the opening, the vibration film is exposed to water and moisture. Since silicon oxide has water permeability, water and moisture permeates the vibration film and reaches the piezoelectric element. Consequently, there is a fear that the piezoelectric material may corrode.